php - How to extract decode JSON from REDCap Array with PHP

Question

I have an JSON Export from a REDCap and it started as a nested ARRAY. I use json_decode, but when I print the result I get an ERROR.

Here is the Array:

[{"record_id":"13","lastname":"Mustermann","first_name":"Json","dob":"1948-10-12","case_number":"1366613"}] 

My Code is:

$deco = json_decode($json);
print $deco;

The line "echo" gives an error. What am I doing wrong?! Thank you